1, Field of the Invention
This invention relates to a universal binding element for binding loose documents in a file.
More particularly the present invention relates to a binding element of the type that allows a bundle of loose documents to be brought together in a unit that is formed by the binding element and the bundle of bound documents being attached in a suitable existing file of any material, whereby use is made of a layer of glue which is meltable under the influence of heat for the purpose of at least joining the loose documents.
2. Related Art
Files which are provided with a supple spine on which a layer of glue meltable under the influence of heat is applied on the inside are already known, for example as described in the Belgian patent no. 869.886 (U.S. Pat. No. 4,441,590). These files are intended as outer covers, through which their utilisation remains exclusively limited to the use of always the same binder.
In order to be able to apply thermal binding systems more universally, binding elements of the already mentioned type were then also developed. They allow a bundle of documents to be bound and at the same time provide a simple attachment of such binding element in any type of binder of file, whether of paper, cardboard, plastic, leather or similar material.
Binding elements of this type are described in Belgian patent application nos. 8701029 and 8800689 (U.S. application Ser. No. 07/477,802).
According to Belgian patent application no. 8701029 use is made of a binding element that principally consists of a spine on which a layer of glue meltable under the influence of heat is applied on the inside and a flap provided along at least one side of the spine which comes sideways along the bundle of documents when binding and which is provided with a double sided strip of adhesive tape on its outside. The loose documents are bound in a thermal manner, while the attachment of the formed bundle to the outer cover is effected by means of the double adhesive tape, which provides for the attachment between the back of the bound bundle of documents and the back sheet of the outer cover.
Notwithstanding the fact that this binding system is very economical in certain applications, its utilisation is rather difficult because two attaching systems are applied, on the one hand, the melting glue and, on the other hand, the double sided adhesive tape. Furthermore, the binding element according to the Belgian patent no. 8701029 is only applicable where the bundle of documents may be attached to the back sheet of the outer cover and whereby the direct attachment of the bundle to the spine of the outer cover is not desired.
From Belgian patent application no. 8800689 a binding element is known that consists of a sheet of relatively stiff material and a strip of glue applied over the length of one edge of this sheet which extends past the sheet. The bundle of documents to be bound, the binding element and an outer cover are brought together in the thermal binding device, after which simultaneously, through the melting of the glue, on the one hand, the loose documents are bound together and, on the other hand, these documents are attached directly to the spine of the outer cover.
Notwithstanding the good results which can also be achieved with the binding element according to the BE 8800689, such binding element presents difficulty when installing the unit in the heating apparatus. The somewhat protruding strip of glue is sometimes difficult to position, whereby this strip can become folded double under the bundle of loose documents, whereby the documents are only partly bound.
Likewise according to the Belgian patent application no. 8800689 the strip of glue overlaps against the outside of the aforementioned sheet, i.e., the side which is directed away from the bundle of documents. With the installation of the outer cover and the melting together of the unit the attachment arises not only between the spine of the bundle of documents and the spine of the outer cover, but also partly between the front sheet of the bundle and the front sheet of the outer cover, which can be undesirable for certain applications. When this binding element is applied by inexperienced people who do not sufficiently press the front and back sheets of the bundle, these front and back sheets may not come into contact with the glue.